The PL16DI module is a 16 channel digital input module. The inputs are
isolated from the logic by bidirectional opto-couplers. The inputs are divided into 2
isolated groups of 8 inputs each. This allows for many configurations in which
the input module may be used. One such configuration could be where one
group is connected as common positive and the second group connected
as common negative.
The counters operate in three modes.
In mode 0: All the counters are disabled.
In mode 1:
The counters are 32 bit counters allowing a count value from
0 to 4294967295. The count value can be cleared by writing a zero to the
associated registers or preset to any other value using the same method.
In mode 2:
The inputs are connected as up/down
counters. Input 1 will increment counter 1 whilst input 2 decrements counter1.
In the same way, inputs 3&4 operate counter 2, inputs 5&6 operate counter 3
and inputs 7&8 operate counter 4,etc.
Note: The count values are not battery backed-up and will be lost if power is turned off. The format of
the registers allows the status of the inputs to be read as either single bits or all at once as a single
register on the Modbus network.