AirChip 3000
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1 OVERVIEW The AirChip 3000 is a programmable, custom designed integrated circuit developed by ROTRONIC and is at the core of an entire family of humidity-temperature measuring devices: o HygroClip 2 (HC2) probes o HC2-AW / HC2-AW-USB probes o HF3 transmitters and thermo-hygrostats series o HF4 transmitter series o HF6 transmitter series o HL20 data logger o HP21 hand-held indicator o HygroMet4 o Custom designed OEM products RO-ASCII is the default communication protocol used by the HW4 software to communicate with an AirChip 3000 device. Users can always use this protocol to communicate...

o The HW4 software is required to set the AirChip 3000 device to use any protocol other than RO-ASCII o When communicating with the HW4 software the AirChip 3000 device automatically switches to the RO-ASCII protocol (ROTRONIC standard). o After using HW4 to configure the AirChip 3000 device to use one of the available protocols power down the device. When the device is powered up, it automatically starts using the selected communication protocol as long as it is not communicating with the HW4 software.

2 AIRCHIP 3000 DIGITAL INTERFACE AirChip 3000 Digital interface Note: a number of devices based on the AirChip 3000 also feature a RS-485 interface 2.1 Communication schematic Communication between the initiator (PC) and the measurement device must also follow the request-answer schematic. It’s not allowed to send a second request before the answer from the measurement device is received. The maximal response time of all devices described in this document is 500 ms.

3 RO-ASCII PROTOCOL RO-ASCII is the default communication protocol used by both the AirChip 3000 devices and the HW4 software. This document describes only some of the commands and functions available with the RO-ASCII communication protocol. In particular, the following functions are not covered here: • Device configuration • 2-point temperature adjustment These functions can be accessed with the ROTRONIC HW4 software. Users who require additional functionality should contact ROTRONIC. Please note that some of the commands and functions not included in this document require a certain...

Other AirChip 3000 devices: Depending on the model, instruments based on the AirChip 3000 feature a USB interface, a RS-485 interface or an Ethernet interface.

The RO-ASCII communication protocol uses exclusively ASCII characters. With the exception of the ERD command, most commands and answers requires very little formatting.

3.3 General command structure RS485 | (vertical bar) this character is required only when the device being addressed is a RS-485 slave (the string is to be passed to the device by another device such as the master or another slave in the RS-485 multi-drop). An AirChip 3000 device may be directly connected by RS-485 to a device such as an Ethernet Server. In that case the AirChip 3000 device is a master device. Do not use the vertical bar | as the start character when sending a data request to a master device. Beginning of the string (curly bracket) Device type identifier (one ASCII...

Notes: o RS485 The vertical bar | is used to indicate that the command string is to be passed to another device connected by RS-485 (multi-drop network with a master and one or several slaves). Upon receiving the string, the master device strips the vertical bar and sends the rest of the string to the RS-485 driver. Depending on the device, the stripped string may also be sent to the PC. The software used by the PC should be designed so as not to confuse this string with an answer. o Adr Address 99 can be used temporarily to communicate with a single device of unknown address. This...

o Checksum character calculation Hex value of checksum character = [(sum of all character Hex values) AND 0x003F] + 0x0020 Note: AND = bitwise AND logical operation This is equivalent to the following Visual Basic code lines: Private Function Checksum(ByVal Data As String) As Char Dim Sum, I As Integer For I = 0 To Data.Length - 1 Sum += Asc(Data.Chars(i)) Next Checksum = Chr(Sum Mod 64 + 32) End Function NOTE: The following characters are not used for the checksum calculation: RS485 character (|), the String end (}) and (CR). The initial ({) must be counted. Example: checksum character for...

The data are returned according to the following structure:

Each individual data element, including the last, is followed by a semi-colon (separator) Examples: {F04RDD} {F04rdd 001; 4.45;%RH;000;=; 20.07;°C;000;=;Fp;-19.94;°C;000;+;001;B2.8;0000000002;HyClp 2 ;006;JAM Note: after changing the HC2 from dew or frost point to “no calculation”, the probe will still send a value after the characters “nc”. This value has no meaning and will disappear after a power reset.

Example: change RS address of probe serial number 0000000002 from 5 to 4 {F05REN 0000000002;4;} {F04ren OKDAM o Note: Address 99 can be used temporarily to communicate with a single device of unknown address. This address causes the device to answer regardless of its address. The actual device address is returned as part of the answer string. Address 99 should not be used when several devices are connected to a network.

Notes: • The HCA command can be used to do a 1-point adjustment of temperature or humidity as well as a multi-point adjustment of humidity. The HCA command cannot be used for a 2-point temperature adjustment. Document E-T-2P TempAdj is available from ROTRONIC for users who are interested in doing a 2-point temperature adjustment. • Adjustment of the HC2 probe is always a two step process. The first step consists in saving at least one calibration point to the probe memory. The second step consists in carrying out the actual probe adjustment. Example of a correct sequence of commands:...

• The effect of an adjustment depends on the number of calibration points present in the probe memory prior to the adjustment: - 1 calibration point: offset adjustment (equivalent to a 1-point adjustment) - 2 calibration points: offset and slope adjustment - 3 or more calibration points: offset, slope and linearization adjustment • Following an adjustment, all calibration points should be deleted from the probe memory Example: {F01HCA 0;0;3;;} Erase all humidity calibration points {F01hca OK(AM