Tonghui TH1941, Operation Manual

Page 1: ...OPERATION MANUAL TH1941 41 2 Digit Multimeter Changzhou Tonghui Electronic Co Ltd www tonghui com cn...

Page 2: ...odels 1951 1961 1941 and 1942 are Installation Category II All other instruments signal terminals are Installation Category I and must not be connected to mains This equipment is POLLUTION DEGREE 2 IN...

Page 3: ...or power line earth ground Always make measurements with dry hands while standing on a dry insulated surface capable of withstanding the voltage being measured The instrument and accessories must be...

Page 4: ...erminals 15 2 6 3 Power up Sequence 16 2 6 4 High Energy Circuit Safety Precautions 16 2 6 5 Power on Defaults 17 2 6 6 Warm up time 17 2 7 Display 17 Chapter 3 Basic Measurements 18 3 1 Preparation 1...

Page 5: ...Selecting the Terminal Character 37 4 5 4 Key Sound 37 Chapter 5 Remote Operation 39 5 1 RS 232 39 5 2 RS 232 Interface Operation 39 5 2 1 RS 232 Connection 39 5 2 2 Sending and receiving data 40 5 2...

Page 6: ...6 3 6 FREQuency and PERiod subsystem 60 6 3 7 HOLD subsystem 62 6 3 8 TRIGger subsystem 64 6 3 9 FETCH Subsystem 64 6 3 10 Common Commands 65 Chapter 7 Specifications 66 Chapter 8 Program Examples 71...

Page 7: ...Peak DC current from 100nA to 20A AC RMS current from 100nA to 20A Two wire resistance from 10m to 20M Frequency from 5Hz to 1MHz Some additional capabilities of Model TH1941 Full range of functions...

Page 8: ...not according to operating instructions Such damage may invalidate the warranty 1 5 Incoming Inspection The TH1941 was carefully inspected mechanically and electrically before shipment After unpacking...

Page 9: ...l wear or failure to follow instructions THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE THE REM...

Page 10: ...riod dB dBm AC DC and diode test 2 Math function keys Select the math function Rel Max Min Comp and Hold 3 2nd Display and speed key Changes reading rate Fast Medium and Slow turns on off the 2nd para...

Page 11: ...C COMP AUTO MAX MIN SHIFT RMT IN LO HI ERR Figure 2 2 Display Annunciators FAST Fast reading rate MED Medium reading rate SLOW Slow reading rate TRIG Indicates external trigger front panel bus selecte...

Page 12: ...value B TRIGger MENU 1 TRIG MOD 2 HOLD WIN 3 HOLD CNT 1 TRIG MOD Select IMMediate Manual or Bus trigger source mode 2 HOLD WIN Set the reading hold sensitivity band 3 HOLD CNT COUNT of readings for re...

Page 13: ...or right Figure 2 3 Menu Tree To turn on the menu press Shift Menu To turn off the menu press Shift Menu or press any of the function or math keys on the front panel To confirm a change on the paramet...

Page 14: ...V 220V 60Hz 50Hz 4 Figure 2 4 TH1941 Rear Panel 1 RS 232C Connector Connector for RS 232 operation Use a standard DB 9 cable 2 Grounding Chassis Grounding terminal 3 Power Line Fuse Holder Assembly TH...

Page 15: ...e ground wire for use with grounded outlets When proper connections are made instrument chassis is connected to power line ground through the ground wire in the power cord Failure to use a grounded ou...

Page 16: ...ments in high energy circuits use test leads and accessories that meet the following requirements Test leads and accessories must be fully insulated Only use test leads that can be connected to the ci...

Page 17: ...de Reading Hold Secondary Display Mode Cal Mode DCV AUTO Medium Local Immediate OFF OFF 1 1 OFF 1 OFF OFF OFF OFF 2 6 6 Warm up time Model TH1941 is ready for use as soon as the power up sequence has...

Page 18: ...aximum resolution 10 V on 200mV range AC technique true RMS ac coupled 1000V Peak AC 3 2 1 Connections Assuming Model TH1941 is under factory default conditions the basic procedure is as follows 1 Con...

Page 19: ...and 100pF CAUTION Maximum Input 750V RMS or 1000V peak 3 107 V Hz Figure 3 1 DC and AC Voltage Measurement Connections 3 3 Measuring Current Model TH1941 current measurement range 2mA 20mA 200mA DC on...

Page 20: ...rom the display CAT 1000V CAT 300V COM 20A T1AL 250V ALL INPUT 1KV MAX 500mA MAX V 1000V MAX DC I AC I Period dB dBm Comp Hold Menu Local 2nd DC V AC V Freq AC DC Rel Rate Esc Shift Trig Auto mA 4 Dig...

Page 21: ...ON Maximum Input 20A DC or RMS Maximum test times 20s Figure 3 2 DC and AC Current Measurements 3 3 2 Front Panel Fuse Replacement WARNING Make sure the instrument is disconnected from the power line...

Page 22: ...n 1000V peak between and COM or instrument damage may occur 5 If the OVL D message is displayed press up key to select a higher range until a normal reading is displayed or press key for auto ranging...

Page 23: ...his assures an equivalent accuracy over the whole frequency range 3 5 2 Gate Time Gate time is the amount of time TH1941 uses to sample frequency or period readings The measurement speed rate and the...

Page 24: ...selected the multimeter alerts you with a beep when a reading is below a threshold resistance level of 10 For other ranges the beeper will sound if a reading is below a threshold resistance level lis...

Page 25: ...ll be selected for diode measurement Note Diode test has a non selectable reading rate of Medium 3 7 1 Connections Assuming Model TH1941 is under factory default conditions the basic procedure is as f...

Page 26: ...asurement function 4 Press to turn on a 2nd display 5 Press or to select a 2nd parameter available 6 Take a reading from the display CAT 1000V CAT 300V COM 20A T1AL 250V ALL INPUT 1KV MAX 500mA MAX V...

Page 27: ...I Hz AC V AC I AC I AC V Percentage Measuring value Comp Measuring value HI IN LO PASS FAIL Max Min Measuring value Max Min Note The measurement range is determined by main measurement function when a...

Page 28: ...ss to enter the parameter level and the present reference value will be displayed 1 00000 4 Use and keys to choose a numerical place and use and keys to increment or decrement the digits Enter a value...

Page 29: ...l be displayed R F 1 00000 4 Use and keys to choose a numerical place and use and keys to increment or decrement the digits Enter a value and units prefix 5 Press ENTER to confirm the reference value...

Page 30: ...n the MATH MEU 5 dBm REF will be displayed 3 Press to enter the parameter level and the present impedance reference value will be displayed REF 0000 4 Use and keys to choose a numerical place and use...

Page 31: ...er automatically selects the appropriate range for each measurement However you can use manual ranging for faster measurements since the multimeter doesn t have to determine which ranging to use for e...

Page 32: ...Actual Input Reference Select a range that cannot accommodate the relative value does not cause an overflow condition but it also does not increase the maximum allowable input for that range For exam...

Page 33: ...command is received 2 The front panel Trig key is pressed TH1941 must be taken out of remote before it will respond to Trig key Take steps below for trigger settings 1 Press Shift to enter the menu o...

Page 34: ...d 5 Use or to select 2 HOLD WIN 6 Press to move down to the command level within the HOLD WIN 7 Use or key to select a window percentage 0 01 0 1 1 10 8 Press ENTER to confirm the selection The messag...

Page 35: ...4 Use or key to move across to the HIGH LIMIT command 1 HI LIMIT will be displayed 5 Press to move down a level to input the high limit value The present high limit value will be displayed HI 1 00000...

Page 36: ...nd does not change when power has been off or after a reset The beeper is enabled when the multimeter is shipped from the factory Use the following steps to change the beeper s state 1 Press Shift to...

Page 37: ...characters LF and CR Perform the following steps to select the terminal characters 1 Press Shift to enter the menu on the menu level A MATH MEU will be displayed 2 Use or key to move across to the SYS...

Page 38: ...5 Press to move down a level to enable or disable the key sound 6 Use or key to turn ON or turn OFF the key sound 7 Press ENTER to confirm the selection The message SAVED will be displayed to show tha...

Page 39: ...performed by a computer via the RS 232 interface 5 2 1 RS 232 Connection RS232C standard now is widely used as the serial communication standard RS232 stands for Recommend Standard number 232 and C i...

Page 40: ...nnection between TH1941 and a computer shown as Figure 5 2 DTR 4 DSR 6 RXD 2 TXD 3 GND 5 RTS 7 CTS 8 2 RXD 3 TXD 5 GND TH1951 Computer Figure 5 2 RS 232 Connection Sketch There may be some difference...

Page 41: ...ect a baud rate 7 Press ENTER to confirm the selection The message SAVED will be displayed to show that the change is now in effect TH1941 will exit the parameter level and move up a level to the comm...

Page 42: ...onses twice One query is recommended to be included in a single command 6 A query response is sent out in ASCII codes with the preset terminal character 7 Several query responses will be sent continuo...

Page 43: ...highest level commands are called the subsystem commands in this manual So the lower level commands are legal only when the subsystem commands have been selected A colon is used to separate the highe...

Page 44: ...essage For example HOLD STATe b The b indicates that a Boolean type parameter is required Thus to enable the HOLD feature you must send the command with ON or 1 parameter as below HOLD STATe ON or HOL...

Page 45: ...after it Example immediate imm Rule exception The short form version of the following command uses only the first two letters of the word TCouple tc If the fourth letter of the command word is a cons...

Page 46: ...new program message must begin with the root command unless it is optional e g FUNCtion If the root is optional simply treat a command word on the next level as the root The colon at the beginning of...

Page 47: ...isable front panel display 1 or ON Enable front panel display Query ENABle Query state of the display Description This command is used to enable or disable front panel display circuitry When disabled...

Page 48: ...elect AC Current CURRent DC Select DC Current RESistance Select 2 wire Resistance FRESistance Select 4 wire Resistance FREQuency Select Frequency PERiod Select Period DIODe Select Diode Testing CONTin...

Page 49: ...le or disable reference Query state of reference 0 1 Use input signal as reference Query reference value 1 1000 ON 0 OFF VOLTage AC NPLCycles n NPLCycles RANGe UPPer n UPPer AUTO b AUTO REFerence n ST...

Page 50: ...ted reading is AC volts ACV 0 to 1010 Expected reading is DC volts DCV DEFault 757 5 ACV 1000 DCV MINimum 0 All functions MAXimum Same as DEFault Query RANGe UPPer Query measurement range of the curre...

Page 51: ...r n 757 5 to 757 5 Reference for ACV 1010 to 1010 Reference for DCV DEFault 0 All measurement functions MINimum Mininum value for specified function MAXimum Maximum value for specified function Query...

Page 52: ...tax VOLTage AC REFerence ACQuire Acquire reference for ACV VOLTage DC REFerence ACQuire Acquire reference for DCV Description When one of these commands is sent the measurement input signal is acquire...

Page 53: ...to 20 Enable or disable reference Query state of reference Use input signal as reference Query reference value 1 20 ON 0 OFF CURRent AC NPLCycles n NPLCycles RANGe UPPer n UPPer AUTO b AUTO REFerence...

Page 54: ...20 Expected reading is AC volts ACI 20 to 20 Expected reading is DC volts DCI DEFault 20 ACI DCI MINimum 0 All functions MAXimum Same as DEFault Query RANGe UPPer Query measurement range of the curre...

Page 55: ...Command parameter n 20 to 20 Reference for ACI 0 to 20 Reference for DCI DEFault 0 All measurement functions MINimum Mininum value for specified function MAXimum Maximum value for specified function...

Page 56: ...Command syntax CURRent AC REFerence ACQuire Acquire reference for ACI CURRent DC REFerence ACQuire Acquire reference for DCI Description When one of these commands is sent the measurement input signal...

Page 57: ...ry auto range Specify reference 0 to 20e6 Enable or disable reference Query state of reference Use input signal as reference Query reference value 1 20e6 ON 0 OFF Speed Commands NPLCycles n Command Sy...

Page 58: ...approximately 20 simply let the parameter n 20 in order to select the 200 range AUTO b Command syntax RESistance RANGe AUTO b Set auto range for Command parameter b 1 or ON Enable auto range 0 or OFF...

Page 59: ...rence n command is coupled to the ACQuire command The last command sent REFerence n or ACQuire eatablishes the reference When a reference is set using the REFerence n command the REFerence Query comma...

Page 60: ...Table 6 6 Table 6 6 FREQency and PERiod Subsystem Commands Summary Command Function Description Default FREQuency THReshold VOLTage RANGe n RANGe REFerence n STATe b STATe ACQuire REFerence Path to co...

Page 61: ...ce Query reference for relative function Descripton These commands are used to establish a reference value for the specified function When reference is enabled REFerence STATe the result will be the a...

Page 62: ...s displaying a 10HZ offset sending this command and enabling Reference zeroes the display This command is functional only if the instrument is on the specified measurement function Sending this comman...

Page 63: ...s COUNt NRf Command syntax HOLD COUNt NRf Command Parameter NRf 2 to 100 Specify HOLD count Query COUNt Query HOLD count Descripton This command is used to specify the count for HOLD COUNt is the numb...

Page 64: ...IMMediate instrument default setting is internal trigger BUS Triggered via RS232 interface MANual EXTernal Press Trig in the front panel for Trigger Query SOURce Query control source Description Thes...

Page 65: ...as below RST Command Syntax RST Description Reset the instrument TRG Command Syntax TRG Description Trigger the instrument for measurement IDN Query Syntax IDN Query return product version LF END Her...

Page 66: ...e Coefficient add 0 1 the applicable accuracy for 0 to 18 and 28 to 40 Relative Humidity Up to 80 for 0 to 28 75 RH for 10M and above ranges of resistance measurement Up to 70 for 28 to 40 Displayed R...

Page 67: ...750 0 V 10 V 100 V 1 mV 1 0mV 100 mV 210 00 2 1000 21 000 210 00 757 5 1 1 1 over range 757 50V is readable at 750V range ACCURACY of reading of range 23 5 Rate Range Accuracy 1 year 1 23 5 20 50 Hz 5...

Page 68: ...ge 23 5 Rate Range Accuracy 1 year 1 23 5 20 50 Hz 50 2kHz 2 20kHz Slow 2 0000mA 20 000 mA 200 00m A 2 0000A 20 000A 1 5 0 5 1 5 0 5 1 5 0 5 2 0 0 5 2 0 0 5 0 5 0 3 0 5 0 3 0 5 0 3 0 5 0 5 0 5 0 5 2 0...

Page 69: ...n 1000VDC or 750VAC for all ranges Open circuit voltage Maximum voltage is 5 5V dc Continuity Range Resolution Full Scale Reading Test Current Accuracy 1 year 23 5 200 100m 999 9 0 5mA 0 1 0 1 Maximum...

Page 70: ...h capacitance 100pF Maximum DCV 500V for all AC ranges Triggering and Memory Reading hold sensitivity 0 01 0 1 1 or 10 of reading Math Functions Rel Max Min dBm dB Compare Limit Test and dBm Reference...

Page 71: ...rt unsigned char code int check_stat int port read serial port state 16bit void send_port int port char c send a character to serial port char read_port int port receive a character form serial port v...

Page 72: ...break if c ps ps else printf nE10 Serial Port Write Echo Error exit 1 send_port PORT n send command end symbol delay 2 while check_stat PORT 256 read_port PORT read string from serial port void string...

Page 73: ...rial port r h ah 2 int14 function2 read character int86 0x14 r r if r h ah 128 if ah 7 be set mean trans error printf nE01 Serial port read error exit 1 return r h al check the status of serial port i...