Cryomech PT415, Installation, Operation And Routine Maintenance Manual

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Specifications
5-12
RS485 Port
The RS485 port can be used to remotely monitor and control the compressor system.
Refer to the compressor’s user guide or contact Cryomech for more information
System I/O Port
The System I/O port is a DB15 female socket that can be used to remotely control the
compressor package and monitor a limited number of its parameters. A detailed
description follows.
System I/O
A 15 pin digital I/O connector with selected input controls and relay outputs is provided
for limited monitoring and control. The digital I/O and its associated DB15 female (socket)
connector are described in this section.
Figure 5-7: 15 Pin connector diagram
Inputs
Three remote inputs are provided to start, stop and inhibit operation of the compressor.
For INPUTS, a low or false is a voltage differential of less than 6VDC (Max1mA) between
the input pin and IN_REF (pin 9). The input pin being – (neg) and the IN_RET pin being +
(pos).
An open circuit (no connection to the input pin) is also low (false).
High or true is a voltage differential between the input pin and IN_RET that exceeds
12VDC. The input pin being – (neg) and the IN_RET pin being + (pos).
Rising edge is a change in the pin state from false to true.
Falling edge is a change in pin state from true to false.
Again, all inputs reference to pin 9. For example, to generate a true condition on an input
connect the input reference IN_REF to a positive DC voltage (greater than 12 volts and