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The suggested Farnell power supply is only 1A and you need 5A for 60W. You might consider a step up transformer to 120Vac and then using conventional 120Vac input/12Vdc power supply of which there are dozens of commercial models.

Well, if you can find a vendor whose remote seal and fill fluid can tolerate 150mbara at your operating temperature, be my guest, but be aware, there are charts or tables showing the limitations of remote seals and their fill fluids at various operating temperatures and vacuum pressures. See...

I doubt the water in the condensate pots is 'flowing' backwards into the steam line, rather I think that the condensate pot water is boiling off in the presence of such a low vacuum. According the the engineeringtoolbox.com site, water at 150mbara boils at 54.4 degC, or 129.9 degF...

I can't help answer your question, but want to congratulate you for your 'rare' ability to clearly communicate in your introductory couple of sentences: what devices you are working with, links to the manuals and clear definition of what you are trying to achieve and where you're stuck. That...

With the right sized actuator, a 3-15psi control manages to move the valve stem on numerous HVAC valves or light duty industrial valves. It does work, if the actuator/spring combination are sized correctly. For heavy duty industrial valves, 3-15psi is also used as the control signal to drive...

RS-422 is the long-distance version of RS-232, both of which are point-to-point hardware layers, so devices using 232 or 422 are not expected to be addressable. Either of my approaches involves a gateway or a converter at each device to establish addressability: 1. If whatever master is...

The Air2O Controls is yet another nominee for the Modbus Hall of Shame - a Modbus RTU implementation with non-configurable slave node ID. There is no published register for the slave node ID. No, there is no magic 3rd party software that does what the manufacturer has failed to implement...

If you're trying to compensate volumetric gas flow measurement for temperature and pressure deviations from design conditions to get an inferred mass flow value, then the attached doc is working example from a single loop controller manual. It does not include a compressability factor.

If you want to put them on a multidrop network and poll them one at a time, then each will require a unique slave node ID number. Sometimes the slave node address is changed with a physical DIP or rotary switch, or jumpers. Other times the slave node ID number is configured in a firmware setup...

The implication of a 32 bit value is that the master has to read two 16 bit Modbus registers in order to get the entire data value. One exception - I do remember running into a slave that did allow the master to read the low order 16 bit word only (data type = 32 bit INT), without throwing an...

MIKEVI seems to have a good grasp of the situation. Read his post three times over. You can check out the link below for Honeywell's public marketing on Turbomachinery Control (click on the Documentation tab)...

Process noise in level applications can come from - agitators creating waves with the crests and troughs (top mounted radar/ultrasonic/IR) - agitator turbulence and flow creates a hydrodynamic force that a hydrostatic head measurement 'sees' but reports it as a presumed hydrostatic force when...

Most of the values on your slave map are floating point values, so they can be displayed as decimal formats like ±XX.xxxxxx or ±XXXXXX.xxxxx, or scientific notation: 3.498523 X 10^-6 The purpose of Modbus is to get binary values representing something or other from one end to other (slave to...

Peter, I salute you. You managed a very coherent and understandable explanation without once mentioning the dreaded "OSI model".

from post #6. >Unfortunately, some manufacturers (at least their sales/support personnel) seem to be misinformed or simply do not know the technical details regarding Modbus communication of their own product (as most of the time communication is just an ancillary function, not the primary...

Take Jschulze's Post #8 advice, by far, the cleanest solution.

1. >1- How can i know that this address is Holding/input/coil/ ? Answer: The map shows a Read/Write column. The portion you included shows only read-only values, but the fact that the choice is indicated indicates that these are most likely Holding Register values. Input Registers are, by...

If the only available hardware network on the device were point-to-point RS-232, then maybe a 'hard-coded' node ID could excused, but even so, a hard-coded node ID is poor form. Another nomination for the Modbus Hall of Shame. >it can't be changed. You sure there's no setup/configuration...

Because the red and black wires are twisted around each other, make sure that the red and black wires are connected directly across the RTD resistance element, with the green wire being the extra compensating wire.

No one on the forum is at your facility, so we don't know - what devices you have - what your network topology is - exactly what works and what doesn't work and when it worked or didn't work Everyone has paper, pencil and a cell phone that takes photos. Please sketch the network with lots of...