Watlow D4T Data Logger
•
76
•
Chapter 5 Function Reference
Signals
Direction
Label
Type
Function
Transmitter - - - -
Digital
Transmitter is inactive (off) when measured resistance is
greater than 100KΩ and active (on) when less than 50Ω
Name
Uniquely identify this FB using up to 20 alphanumeric characters.
Direction
To configure the I/O point to detect a contact closure, set Direction to Input Dry Contact.
Output
Use this function to switch an external device. This FB is found on the canvas of the FB dia-
gram. The number of these FBs that are available depends on the number of digital I/O flex
modules installed and configured as outputs.
Signals
Direction
Label
Type
Function
Receiver
- - - -
Analog
(%)
or Digital
Off or 0%: the output is off.
Between 0% and 100%: the output switches according to
the Time Base Type setting.
On or 100%: the output is on.
Name
Uniquely identify this FB using up to 20 alphanumeric characters.
Direction
To configure the I/O point to drive the physical output, set Direction to Output.
Time Base Type
Choose the method used to operate the output when the input is an analog percentage. With
either of the methods, the output switches off and on such that the average amount of time
the output is on equals the desired percentage.
Note:
The type of field device connected to the output determines how frequently it can be
switched.
Options:
• Fixed Time Base
: the percent output power is con-
verted to a duty cycle over the Fixed Time Base. For
example, if the Fixed Time Base is ten seconds and 75%
power is called for, the output turns on for 7.5 seconds
and off for 2.5 seconds, and repeats as illustrated be-
low. This is appropriate for mechanical relays.
• Variable Time Base
: the output switches as often as every three ac line cycles. For
example, when 66% power is called for, the output is on for six ac cycles and off for