Rockwell Automation 1771-CFM Config. Flowmeter Installation Instructions - Manual (Page 12)

Configurable Flowmeter Module 12
Publication 1771ĆIN043B-EN-P - July 2002
Configure the Module
To configure the CFM module, you enter
BTW and BTR instructions into your ladder
logic, then you enter data into the BTW
instruction. This data should conform to the
input device and specific application that you
have chosen.
You can configure the module using I/O
configuration software or by editing bits in
the BTW instruction.
During normal operation, the processor
transfers 1 to 60 words to the CFM module
when you program a BTW instruction to the
CFM module’s address.
IMPORTANT You must program at least one
BTW, with a word length of 4,
to get useful data back from the
CFM module.
Your PLC processor gets data from the
CFM module using BTR instructions in your
ladder logic program. The CFM module
transfers up to 41 words to the PLC
processor’s data table file. The words
contain module status and input data from
each channel.
You should program a block transfer read
length of zero (0). When a BTR of 0 is
programmed, the CFM module will
determine the correct number of words (41)
to return.
Input Capabilities
The CFM module accepts input for up to four channels
(mode dependent). Each of the four input channels may
accept these input signals:
•
magnetic pickup — 50mV to 30V ac
•
3-30V dc pulses with open collector (TTL compatible)
•
proximity probe inputs
– compatible with Bently Nevada 3300
(5mm and 8mm) proximity transducer systems
– provides two isolated 24V dc power supplies
(rated at 12mA) to power external devices
Output Capabilities
The CFM module has four assignable outputs. These
outputs are designed for applications that require fast
response. The outputs:
•
are electronically current limited to 2A
•
can be assigned to any input channel with user-selectable
turn-on and turn-off values
•
are current sourcing at 5-30V dc (1A maximum per
output)
•
must be connected to an external power supply
•
are in groups of two — this lets you use two separate ex-
ternal power supplies if desired (one for outputs 0&1 and
one for outputs 2&3)
Outputs may be forced on or off independent of count or
frequency value. They may be forced on and off by setting
bits in the BTW configuration block.
IMPORTANT You can assign as many as four outputs to a
given channel; however, you can not use the
same output with two different channels.