CONTREX CX-1200 - Manual (Page 5)

CX1200 rejects that setpoint, and retains the present or existing setpoint (presumably the
value entered by the operator). This technique addresses the fact that the polling list, or
polling action, is not easily modified on-the-fly. It is easier to just substitute the
"unreasonable" number for the polled parameter value. The PLC can also use this
technique to monitor the operator's manually entered setpoints. By reading the operator's
entry, the PLC can over-write it with a different number if it is determined that the
operator entered an inappropriate value.
Powering the DeviceNet option card:
. The DeviceNet option card requires more power (the spec says 250ma at 5vdc, but it
actually draws less) than is available from the controller. This power requirement
(applied at JB2 – the 2 pin connector) is for the on-board processor, and should not be
confused with the normal external 24vdc power that runs the DeviceNet network itself
(applied at JB1 – the 5 pin connector). An external power supply at 5vdc, 300 ma is
required. The CX1200 has a 12vdc supply that is intended for encoder use. This 12vdc
is NOT acceptable for the DeviceNet card. An external supply is required. You may use
any brand or style, but for reference, you could use DigiKey catalog number T309-ND,
rated 300ma at 5vdc +/- 5% at approx $10 cost.
Filename:
dnetguid1200.doc