S
I have a lot of experience with all sorts of PLC's (AB & Modicon) and Scada (WW/iFix. etc). and Delta-V
I have looked carefully at the $ per I/O point which I can get from a PLC vendor, vs. the Application Specific HW available for Air Handler/HVAC control, and find the HVAC HW significantly less expensive, but programming
is more cumbersome. E.g. direct input for very low cost but accurate thermistors.
We have found custom function blocks in IEC1131 a lot easier to deal with than the Lonworks equipment.
Have any list members used a lonworks system for HVAC control? And have had a good experience with it vs. PLC's?
Ideally I would need distributed control, connected by a network, to single HMI. Where it is easy to duplicate code among nodes. Use relative addressing for HMI tags, all the things which lonworks promises to offer, but with real programmability at each node.
If you have evaluated these technologies for HVAC control, and have come up with HW/SW solution, which a DCS/PLC engineering would find usable, please feel free to contact me off-list for further discussions.
Steven Landau
VP Controls & Automation
SPEC process engineering & construction
92 Montvale Ave
Stoneham, MA 02180
T. 7814383337
F. 7814385297
I have looked carefully at the $ per I/O point which I can get from a PLC vendor, vs. the Application Specific HW available for Air Handler/HVAC control, and find the HVAC HW significantly less expensive, but programming
is more cumbersome. E.g. direct input for very low cost but accurate thermistors.
We have found custom function blocks in IEC1131 a lot easier to deal with than the Lonworks equipment.
Have any list members used a lonworks system for HVAC control? And have had a good experience with it vs. PLC's?
Ideally I would need distributed control, connected by a network, to single HMI. Where it is easy to duplicate code among nodes. Use relative addressing for HMI tags, all the things which lonworks promises to offer, but with real programmability at each node.
If you have evaluated these technologies for HVAC control, and have come up with HW/SW solution, which a DCS/PLC engineering would find usable, please feel free to contact me off-list for further discussions.
Steven Landau
VP Controls & Automation
SPEC process engineering & construction
92 Montvale Ave
Stoneham, MA 02180
T. 7814383337
F. 7814385297